• Clinical and Experimental Pediatrics
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• v.46 no.2
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• pp.122-127
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• 2003

Purpose : Baby-walkers are used by many parents because of the convenience they provide in keeping children occupied, quiet, happy, and in stimulating ambulation. But, these devices have more risks than benefits. Therefore, we performed a study to evaluate the effects of baby-walkers on motor development of human infants according to the hours used in a day, total duration(months), and types of injuries associated with the walkers, and to establish effective methods. Methods : 1,045 questionnaires were filled out by parents who had a baby whose aged between 8 months and 15 months that visited local pediatric clinics and medical centers in Chonju and Iksan from May 1, 2002 to July 31, 2002. They were analyzed in a control group that didn't use babywalkers, a low-user group that used baby-walkers less than 2 hours a day and a high-user group that used them more than 2 hours a day. Results : The mean age of the 1,045 babies whose parents responded to the question investigation was $12.6{\pm}2.4$ months. The number of babies who used the baby-walkers were 811(77.6%). Crawling and walking alone were delayed in the high-user group. The parents who knew the side effects of the baby-walkers totalled 392(48.3%). Conclusion : The findings of this study revealed that many parents didn't know the effects of baby-walkers on motor development in their infants and the risks associated with baby-walkers. Therefore, we should educate parents on the risks of baby-walkers and recommend reducing the use of baby-walkers.

• Economic and Environmental Geology
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• v.50 no.2
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• pp.171-180
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• 2017

This study performed the analysis on the volcanic gases and hot spring waters from the Julong hot spring at Mt. Baekdu during the period from July 2015 to August 2016. Also, we confirmed the errors that $HCO_3{^-}$ concentrations of hot spring waters in the previous study (Lee et al. 2014) and tried to improve the problem. Dissolved $CO_2$ in hot spring waters was analyzed using gas chromatograph in Lee et al. (2014). Improving this, from 2015, we used TOC-IC to analysis dissolved $CO_2$. Also, we analyzed the $Na_2CO_3$ standard solutions of different concentrations using GC, and confirmed the correlation between the analytical concentrations and the real concentrations. However, because the analytical results of Julong hot spring water were in discord with the estimated values based on this correlation, we can't estimate the $HCO_3{^-}$ concentrations of 2014 samples. During the period of study, $CO_2/CH_4$ in volcanic gases are gradually decreased, and this can be interpreted in two different ways. The first interpretation is that the conditions inside the volcanic edifice are changing into more reduction conditions, and carbon in volcanic gases become more favorable to distribute into $CH_4$ or CO than $CO_2$. The second interpretation is that the interaction between volcanic gases and water becomes greater than past, and the concentrations of $CO_2$ which have much higher solubility in water decreased, relatively. In general, the effect of scrubbing of volcanic gas is strengthened during the quiet periods of volcanic activity rather than active periods. Meanwhile, the analysis of hot spring waters was done on the anion of acidic gases species, the major cation, and some trace elements (As, Cd, Re).